Particulate catalysts used in certain fluid-solid reaction systems, such as alkane or alkyl aromatic dehydrogenation, must typically be separated from the reaction product and either recycled into the reaction system or regenerated prior to being recycled into the reaction system. In either case, the solid catalyst particles must also be separated from the regenerator system effluent. The most common method of separating the solid catalyst particles is by maintaining the regenerator bed at velocities near (0.914 meter per second (m/s) (3 feet/second (ft/s)) and allowing particle disengagement to reduce the quantity of catalyst, by controlling entrainment, to one or more high velocity cyclone separators, such that the gas flow velocity upon impacting a first cyclone separator may range from 16.8 meters per second (m/s) (55.1 ft.s) to 25.9 m/s (85 ft/s). Such high gas velocities result in high impact velocities of the solid catalyst particles on the cyclone walls, resulting in catalyst particle attrition. Bubbling bed regenerators for a dehydrogenation system, wherein the dehydrogenation catalyst and entraining gas exits the bubbling bed at about 1 meter per second are well known.
Dehydrogenation catalysts are known to contain higher platinum concentration on the outer surfaces of the particle than in the bulk of the catalyst particles due to migration of expensive metal components, such as Pt, Ga, Pd, Au, Ag, at high temperature. Therefore, as the dehydrogenation catalyst particles are attrited, the most active catalyst component may be lost as fine particles, leaving the remaining catalyst particle with a lower activity. Dehydrogenation catalysts tend to be very expensive, primarily because of the Pt component, which is most affected by catalyst particle attrition. However, fluid-solid reaction system catalyst particles further include other costly components, such as alumina-silica support. Therefore, minimization of catalyst attrition, particularly of PDH catalyst particles, would be beneficial to the economic viability of such fluid-solid reaction systems, and particularly to PDH processes.